A prior art search was conducted and disclosed the following references. In general, azimuth/elevation mounts of the prior art use expensive precision bull gears subject to both gravity and overturning loads. The mount of the present invention decouples the paths for gravity and overturning loads. This is accomplished by means of a novel wheeled turret (6), torque tube (11), and mechanically advantageous drive wheel (12).
U.S. Pat. No. 3,713,727 is a point focusing solar concentrator. The reflector has an overall paraboloidal shape as compared with the overall spherical shape of the reflector of the present invention. The individual reflective facets have variable shape and are flat, whereas the facets in the present invention have a uniform size and are shaped as spherical sections. The azimuth/elevation mount shown in the patent uses a turntable with sector and bull gears, whereas the present invention uses a torque tube, drive wheel, chain and sprocket. The base of the concentrator depicted in the patent uses multiple vertical support legs, rather than the tripod frame of the present invention. Unlike the present invention, the patent design has no application to the production of electricity or industrial process heat in large, economic quantities, nor is the concentrator intended for low cost mass production. Rather, it is an assemblage of parts intended as a solar furnace with specialized specimen handling features for isolated laboratory testing of materials.
U.S. Pat. No. 3,977,773 is a point focusing solar concentrator having an overall paraboloidal shape, rather than the overall spherical shape of the reflector of the present invention. The reflective facets are tiny, flat, rectangular tiles, and have variable shapes, whereas the present invention uses uniform sized facets having a spherical contour. The mount of the device described in the patent is a polar mount rather than the azimuth/elevation mount of the present invention.
U.S. Pat. No. 811,274 is a line focusing, rather than a point focusing, device because the overall spherical shape of the reflector combined with the non-Fresnelled contour facets give this type of focus. The present invention, on the other hand, is a point focusing concentrator. The mount in the patent uses a center post on a circular track for azimuth with double lead screws for elevation, whereas the present invention advantageously uses a turret and torque tube for azimuth and a single lead screw for elevation. The use of two lead screws, perhaps mandated by the great weight of this patent's reflector, is unfortunate because of the potential for binding due to unequal travel along the two screws. The base in the patent uses a track and central pintle, whereas the present invention advantageously uses a tripod frame.
U.S. Pat. Nos. 4,129,360; 4,266,530; and 4,284,061 are not point focusing devices, and therefore not directly relevant to the present invention.
"Mirror on the Sun", Jet Propulsion Laboratory, JPL 400-10, October 1980, discloses a solar test bed concentrator with a reflector having an overall paraboloidal shape, not a spherical shape as in the present invention. There are no spaces between panels as in the present invention.